1. Field of Invention
This invention relates in general relates to HVAC systems, and in particular to air flow straigtener within an air duct.
2. Background of Related Art
Vehicle HVAC systems include an air duct system having a plurality of register openings for delivering conditioned air to a vehicle interior. The vehicle air duct system typically includes a primary air duct having one or more secondary ducts for providing forced air to various locations of the vehicle. The secondary air ducts branch off from the primary air duct for delivering the forced air to predetermined locations of the vehicle. Registers are ventilation openings integrated into the instrument panel/console or other interior trim work of the vehicle that allow the forced air to enter the vehicle interior from the air duct system. The registers typically include a plurality of pivoting vanes for directing the air flow as it exits the register opening and into to the interior of the vehicle. Such registers are typically located within or below the front instrument panel.
As is common in most vehicles, the primary air duct runs substantially parallel with the vehicle's front instrument panel. A secondary air duct branches off the primary air duct at a substantially perpendicular angle. The secondary air duct extends at a substantially perpendicular angle to the front instrument panel. However, the front instrument panel is not a single planar surface. Rather, the front instrument panel may include various planar surfaces, or even non-planar surfaces for that matter, juxtaposed to one another which form the front instrument panel. As a result, due to the varying angles at which the planar or non-planar surfaces are formed to one another, the respective air duct may be coupled to a respective area of the front instrument panel at an angle other than 90 degrees. As a result of such a coupling of the respective air duct to the front instrument panel, the register opening may not be positioned parallel with the flow of air exiting the respective air duct. That is, the register opening may be mounted to the air duct which results in at least a portion of the air flowing through the opening of the air duct being non-parallel to the register opening (i.e. non-parallel with the vanes in the register opening). The abrupt change of direction as the airflow passes from the duct to the register results in turbulent air flow. The turbulent air flow passing by the vanes of the register opening causes audible NVH to a passenger of the vehicle as a result of the turbulent separation of the airflow streams.